


A Lesson on Oviparous Breeding

by Dark_Crystal_Demon



Series: Undertail University [2]
Category: Undertale (Video Game)
Genre: Anal Sex, Anatomy, Breeding, Clinical Anatomy Lesson, Clinical Gaster, Consensual Kink, Consensual Sex, Each Volunteer Gets There Own Clutch, Ecto-Penis (Undertale), Egg Laying, Explaining Hybrid Creation, Hybrids, Impregnation, Knotting, Multi, Oral Sex, Oviposition, Professor Gaster, Vaginal Sex
Language: English
Status: Completed
Published: 2017-04-19
Updated: 2017-04-19
Packaged: 2018-10-20 20:11:51
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,569
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10669935
Author URL: https://archiveofourown.org/users/Dark_Crystal_Demon/pseuds/Dark_Crystal_Demon
Summary: Gaster continues his lessons to educate monsters on breeding with humans.This lesson he focuses on monsters that procreate with oviposition: egg laying.He'll demonstrate different implantation methods using three volunteers of different genders to highlight each technique.





	A Lesson on Oviparous Breeding

**Author's Note:**

> This fic goes out to all the ovi-kink lovers who have blown me away with their thirst for [OviBlaster](http://archiveofourown.org/works/10661442). Seriously, your enthusiasm inspired another oviposition fic out of me. Though this is quite different. 
> 
> Undertail University is a series written as lectures. It's based off my love for great audio smut. I don't have the means to make them myself, but one day I hope to listen to a clinical Gaster describe his techniques and tips for breeding... It's a personal kink of mine, and I hope you enjoy.

Welcome to my lesson on Monster Oviposition With Humans. If you read the texts I assigned for this lesson, then you already know that some monsters are oviparous. However, breeding of humans with oviparous monsters is not very complicated. It's a simple soul bond during egg creation. The challenge comes after the eggs are laid when the partners must focus their energy on protecting and maintaining the nest... this is uninteresting for the purpose of this study.

No, this oviparity lesson will focus on ovoviviparous monsters. These monsters require eggs to be laid internally and incubated within the body, preferably the human, as the host. Human souls are extremely strong and can continuously feed a larger amount of eggs than most monsters. This is ideal for those desiring a large clutch.

As a side note, this lesson can also be useful for those monsters that are endoparasitic, or just need a receptacle for their eggs. The university frowns upon parasitic use of humans, but it has been observed that humans are the most resilient at surviving such encounters.

Some monsters, like myself, can switch reproductive techniques. Viviparity, or live birth, is preferable for some, but ovoviviparity has its advantages. The first advantage I've already mentioned: it results in a large amount of offspring within one incubation cycle. There are current studies researching whether being born from a clutch will hinder a hybrid's ability to reach boss monster level. However, these studies still need years before any conclusive results can be determined.

The second advantage to oviposition is that it is less reliant on the physical gender of your human. Egg clutches take far less energy to maintain within a human than a live embryo that needs space to grow and move during its gestation. For development of a growing embryo, humans with a biological womb are ideal since their uterus can be easily modified as needed. Those without a womb in the species will require much more magical upkeep...

But I digress. That is a lesson for another time.

The third advantage to oviposition is that it **_doesn't require consent_**.

Mmm?

Oh, _perhaps I should phrase that differently_.

I mean that it requires very little from the human. Once inside their body, the eggs will automatically link to a human's soul and receive their nutrients as well as human traits. We have observed that within a single clutch, a variety a hybrids can emerge with differentiated degrees of monster and human traits.

Please, be at ease. As the university requires, this lesson will only be demonstrated using consensual oviposition.

We'll be using three volunteers to perform the most common methods of ovoviviparity. I will start with the female for uterine implantation. Then I will move on to another human to demonstrate oral implantation. And we will then end our lesson with an anal implantation using a male of the species. Please note that all humans can be used for the last two methods. Only the first method is exclusive to humans with wombs.

This lesson is being recorded for university records and will available online. My videographer tells me they'll be labeling each type of insertion for easy browsing. This will allow you to skip ahead to a particular implantation technique, if you so choose.

All volunteers have signed their consent and remain blindfolded to protect their identity.

** UTERINE IMPLANTATION **

Uterine implantation is very similar to viviparous copulation. The more stimulated the female, the more slick her canal will be to accept you. I will refer you back to my previous [lesson on female anatomy](http://archiveofourown.org/works/8743144) if you want details on how best to stimulate your female.

However, as I stated before, there is very little required of humans in oviparous breeding. Her orgasm is not even required.

Don't frown, pet. Based on your interview, penal insertion was all that was needed for your pleasure. Your overdeveloped Gräfenberg spot will unquestionably be stimulated during this entire process.

For the sake of time, I will lubricate this female and... ah... see how easily my phallus can slide inside her tight canal? Never underestimate the convenience of a lubricated entrance. Her moans indicate she takes pleasure from the insertion. This is a good sign for a pleasant implantation.

While you're inside her, you'll want to stretch her out further. For a magical phallus, you simply increase your magic and widen the girth of your penis. She'll try to squirm away during the widening process. Bondage is always a wonderfully effective method in keeping humans still. Or, simply grip her hips firmly, like so, and keep her in place. Sliding your cock in and out with a steady rhythm will also help her adjust. I recommend this technique while gradually increasing your size.

Keep up this pace until she is the correct width to accommodate your eggs.

A word of warning for first time breeders, humans tend to move erratically during the process even when they are at their most obedient and especially when they are experiencing orgasm. The best way to prevent the loss of any eggs during the process is to create a knot, magical, natural, or artificial. You see this large bulge at the base of my shaft? As I slide it into her...

Oh... one moment...

Pet, you're so tight.

I'll lift your leg... ah, yes. There. Oh no, no, pet. You mustn't moan that loudly. I know my size is incomparable, but the audience needs to hear me.

That's right. Good girl.

Now she is ready for implantation.

Ah-As my first egg travels down inside her, you can see its glow through her skin. This is normal. Getting the egg into her womb can be a bit tricky. Her cervix loosens open more with an orgasm, but you can also just use **_force_**.

_AHHHH!_

Oh, pet. If you scream like that again, I will have Sans bring out the gag. That's a good girl. Only eleven more to go.

What I just did was concentrate my will into my magic and force the egg to phase through her wall and into her womb. You can see it's faint glow... there.

However, getting her will involved will speed up the process. It's easier to impregnate her if she is enjoying herself. This is why I will now complete the rest of these transfers by focusing my attention on her clitoris and having her repeat words that will instruct her own energy in assisting me. Observe.

Tell me what you want.

_Your seed inside me - AH!_

Good girl, you took that one so well. Do you want me to give you another?

_Yes! Yes! AH!_

You like carrying my eggs?

_Yes, Ma-AH-ster._

You are so obedient. Look at how you glow with my seed.

_I'm glad. I want to ple-AH-se you -AH AH AH!_

Mm, you can take so many when you're about to cum. Look at how much you're shaking, pet. Cum for me.

_AH! AH! AH! AHHHHHH!_

Good girl. Now breathe to help your body stretch more. You'll be more comfortable in a few minutes as they settle down.

You see how the dialogue exchange and the clitoral stimulation made a difference? I prefer this method. A willing human is always more efficient than an unwilling one.

Finally you have to fertilize the eggs, but that is just a simple ejaculation. For the sake of time, I fertilized with that last thrust and egg drop. You can see the glow of the eggs swimming inside her. At this moment, her soul is linking to each egg and beginning to nourish them with her energy.

You may find that your humans are a little weaker at the beginning of incubation. This will gradually change as the eggs themselves become stronger. When they start sending energy back to her, their souls will have fully formed along with their bodies. Soon their determination will force her body to contract and send them out for hatching.

** ORAL I ** ** MPLANTATION **

Ah, my next volunteer is non-gendered. They/them. Though we are doing an oral insertion, I have asked them to also be naked in order to allow you the visual of the eggs that will accumulate inside their stomach.

I must emphasize the need to make sure the eggs travel all the way down a humans esophagus and the importance of only filling their stomach. Use of their lung sack or intestines is not recommended as that may kill the human through vital organ blockages.

Please also keep in mind that a human's stomach is digestive in nature. Only those with magically protected shells should attempt this method.

If you follow those guidelines, you will find that this insertion technique is quick and easy to perform with any human.

I prefer the human to be on their knees. See how perfectly their mouth lines up with my phallus? Notice the way they are drooling at the thought of my penis in their mouth? This is a perk to consensual implantation; they biologically with lubricate for you.

As we saw in the last demonstration, humans tend to squirm even when they are consenting. In order to ensure I do not lose an egg, I hold the back of their head, firmly grasping their hair as they allow me inside their mouth.

Ah. Yes. Good.

Give your human encouragement as they take your entire length inside their oral cavity. Some may have a gag reflex as you reach the back of their throat. This is normal. You can insert eggs even as they're gagging, but I would turn off your nerve sensors as they will try to bite you. If you are not using a magical appendage and prefer to listen to them gag, I would recommend removing their teeth or armor plating your shaft with some sort of protection.

To avoid gagging, gradually insert yourself, like so. Watch them carefully as you push inside inch by inch. When they start to gag, pull back. You need not go that far. The back of their tongue and esophagus will guide your eggs instinctively down into their body.

Watch, I will deposit my first egg. Make sure they're lubricated. See how easily they swallowed that first one? Watch the glow of my egg down their throat. The glow disappears as it enters their chest cavity and down within their stomach. This is normal. There are more organs and cells that obscure the light within their stomach. However, as you build up the clutch, you will begin to see their skin glow - if you are using magical eggs, of course. For those of you with opaque, natural eggs, you'll still begin to see their stomach extend depending on the size of your clutch and your human.

Ah, you're doing a good job. Yes. Take another.

They may start to tear up. This is normal. Humans become very emotional as they feel their body stretching with your eggs. It can also be straining on their jaw muscles. You can massage them, like so, and mmm... they may close around you more. This can be a great way to stimulate yourself for the fertilization portion of your session.

See how their stomach is beginning to glow? When the eggs are ready, you can either induce vomiting or allow the eggs to drop into the intestines one by one.

Ah, yes, that is the last one for this volunteer. Give me a moment to fertilize these and then we will move on to the next subject.

Mmm... ah... yes... open wide... you are doing so well. I'm... I'm going to cum... be good and swallow every drop? Yes... Ahhhh.

Ah, you're so diligent with that tongue. Good job, pet. Yes. Very good job.

** ANAL I ** ** MPLANTATION **

My last subject will need to be relaxed. Anal insertion has many more psychological components when trying to deal with the internal sphincter. I will give you a lesson on male stimulation and anal relaxation in a different lesson. Today we are focusing on the implantation itself. 

As with the female, lubrication is key. Anal, even with an experienced mate, takes more time to prep. Starting with a finger and gradually increasing the numbers until you can fit your phallus inside their anus is a gradual process. As I go through this process, I will explain the two forms of anal implantation: momentary and dilatory. 

Momentary implantation is for eggs that only require a short incubation and brief connection to your human. Momentary has also been known as soul fertilization. After a brief incubation, the egg remains unhatched for many days outside any host. Similar to common oviparity, momentary implantation will require a nest. Since it only requires brief implantation, the eggs are stored in the rectum. 

My eggs require a much longer gestation period. This means the eggs need to rest within his stomach. Oral implantation is the quicker way to achieve this goal. However, many mates prefer the intimacy of anal. This, to me, is dilatory in essence. However, many enjoy the feeling of the eggs moving through their internal track system. It also requires a large amount of intimacy as this process can take up to a day to complete and requires the oviparous monster's magical manipulation of the eggs throughout the entire process.

Many here are assuming this is why I left this human for last. Even after this lesson, I will have to focus energy in the eggs path until they are all safely implanted. However, I have found a method that speeds up the process and allows me freedom to work on other projects even while the eggs are still travelling inside him.

Though many will prefer the traditional method, I will demonstrate my technique by revealing an egg. 

As you can see, this black sphere in my hand is one of my eggs. Since my own reproduction is entirely magically produced, I can manipulate the shape of the egg. With enough energy...

There. You see? I have forced it to adapt a tail. This will allow it self propulsion inside his body. I, of course, based this design off of human sperm cells. When my egg reaches his stomach, it will implant its tail within the wall lining of his organ. This egg's independence is difficult to master, but useful when you want to implant using the anal canal. 

Ah, he's ready. Good boy. Your obedience is pleasing. 

In some ways, anal is much more efficient at expelling eggs with a human. Notice my rhythm as I glide into him. I'm slow at first, but soon that will change. This one enjoys rough and hard thrusts. 

 _Ah-ss_ I increase my _rh-Ah-thm_ , my grip on his hips should be _-Ah-nough_ to keep him in place. Make sure you're _-Ah-ways_ pressing _-Ah-gainst_ his _pr-Ah-state._

You naughty boy, the way you squeeze me as I am trying to teach. I'm going to fill you with twice as many eggs as last time. 

I can now release one egg after another in quick session to swim inside him until they reach his stomach. 

I am afraid we've run out of time. If you would like to stay after class, the end of this method will also reveal how far a human's stomach can extend with eggs. 

Don't whimper, pet. You're going to need to save your energy to feed this clutch. It's going to be my largest one yet.

Class dismissed.   

**Author's Note:**

> Did you enjoy the lesson? Which implantation was your favorite? 
> 
> I dedicate this fic to WDGaster who patiently waited for this kink to come to life in my work. Thanks for the inspiration! 
> 
> Thank you for reading! Please share your thoughts below and follow me on [Tumblr](https://www.tumblr.com/blog/darkcrystaldemon) for more smut cannons, recommendations, and shares.


End file.
